From 9888e6fa7b68d9c8cc2c162a90979825ab45150a Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 6 Mar 2006 17:44:43 -0800 Subject: [PATCH] slab: clarify and fix calculate_slab_order() If we triggered the 'offslab_limit' test, we would return with cachep->gfporder incremented once too many times. This clarifies the logic somewhat, and fixes that bug. Signed-off-by: Linus Torvalds --- mm/slab.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index 2b0b1519bb74..f2e92dc1c9ce 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1628,36 +1628,36 @@ static inline size_t calculate_slab_order(struct kmem_cache *cachep, size_t size, size_t align, unsigned long flags) { size_t left_over = 0; + int gfporder; - for (;; cachep->gfporder++) { + for (gfporder = 0 ; gfporder <= MAX_GFP_ORDER; gfporder++) { unsigned int num; size_t remainder; - if (cachep->gfporder > MAX_GFP_ORDER) { - cachep->num = 0; - break; - } - - cache_estimate(cachep->gfporder, size, align, flags, - &remainder, &num); + cache_estimate(gfporder, size, align, flags, &remainder, &num); if (!num) continue; + /* More than offslab_limit objects will cause problems */ - if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit) + if ((flags & CFLGS_OFF_SLAB) && num > offslab_limit) break; + /* Found something acceptable - save it away */ cachep->num = num; + cachep->gfporder = gfporder; left_over = remainder; /* * Large number of objects is good, but very large slabs are * currently bad for the gfp()s. */ - if (cachep->gfporder >= slab_break_gfp_order) + if (gfporder >= slab_break_gfp_order) break; - if ((left_over * 8) <= (PAGE_SIZE << cachep->gfporder)) - /* Acceptable internal fragmentation */ + /* + * Acceptable internal fragmentation? + */ + if ((left_over * 8) <= (PAGE_SIZE << gfporder)) break; } return left_over;